Self-organized pigmented and vascularized full skin tissue model for melanoma research

Being a multi-layered organ, the complexity of human skin is
difficult to mimic in vitro. Despite the major advances in currently
available 3D skin models, they remain very simplistic in
relation to native tissue complexity. Moreover, the integration of
melanoma cells into 3D skin models rendering representative tumor
microenvironments is yet to be fully achieved. Cell sheet
engineering has shown impressive results in recreating the native
tissue structure and interactions of many different tissues by
keeping intact the native cell-cell and cell-extracellular matrix
interactions (Yanf et al., 2007; Haraguchi et al., 2012). Considering
these major features, we built a 3D full skin model by stacking
heterotypic cell sheets of human dermal fibroblasts (hDFbs)
and keratinocytes (hKCs) or of hDFbs and human dermal microvascular
endothelial cells (hDMECs), respectively as units of the
epidermis- or dermis-like analogues. Melanocytes were further
incorporated in the epidermis-like cell sheets before exposed to
air-liquid interface (ALI), obtaining a pigmented stratified epidermis.
In order to understand how melanoma cells responded
to the self-organized full skin model, different cell lines (WM-
115, SK-Mel-28, LM-MEL-33 and VMM15) were used. Histologically
analysis confirmed the organization of those cells within
the epidermis and their migration into the dermis through the
formed basement membrane. Interactions between the melanoma
cells and the stromal cells in the dermis are being assessed
focusing on the known mechanisms involved in tumour progression
in order to validate our approach.